Measurement and Signature Intelligence, or
MASINT, refers to intelligence
gathering activities that bring together disparate elements
that do not fit within the definitions of the major disciplines
mentioned above.

Formally recognized by the United States
Department of Defense as an intelligence discipline in
1986,[1][2]
MASINT is technically derived intelligence that - when collected,
processed, and analyzed by dedicated MASINT systems - results in
intelligence that detects and classifies targets, and identifies or
describes signatures (distinctive characteristics) of fixed or
dynamic target sources. In addition to MASINT, IMINT and HUMINT can
subsequently be used to track or more precisely classify targets
identified through the intelligence process. While traditional
IMINT and SIGINT are not considered to be MASINT efforts, images
and signals from other intelligence-gathering processes can be
further examined through the MASINT discipline, such as determining
the depth of buried assets in imagery gathered through the IMINT
process.

One vivid image of MASINT, by William K. Moore, is that "MASINT
looks at every intelligence indicator with new eyes and makes
available new indicators as well. It measures and identifies
battlespace entities via multiple means that are difficult to spoof
and it provides intelligence that confirms the more traditional
sources, but is also robust enough to stand with spectrometry to
differentiate between paint and foliage, or recognizing radar
decoys because the signal lacks unintentional characteristics of
the real radar system.

MASINT is exceptionally valuable in detecting deception

At the same time, it can detect things that other sensors cannot
sense, or sometimes it can be the first sensor to recognize a
potentially critical datum."[3]

It can be difficult to draw a line between tactical sensors and
strategic MASINT sensors. Indeed, the same sensor may be used
tactically or strategically. In a tactical role, a submarine might
use acoustic sensors—active and passive sonar—to close in on a target or get away from a
pursuer. Those same passive sonars may be used by a submarine,
operating stealthily in a foreign harbor, to characterize the
signature of a new submarine type.

It can also be difficult to draw the line between MASINT and technical intelligence
(TECHINT). A good distinction is that a technical intelligence
analyst often has possession of a piece of enemy equipment, such as
an artillery round, which can be evaluated in a laboratory. MASINT,
even MASINT materials intelligence, has to infer things about an
object that it can only sense remotely. MASINT electro-optical and
radar sensors could determine the muzzle velocity of the shell.
MASINT chemical and spectroscopic sensors could determine its
propellant. The two disciplines are complementary: consider that
the technical intelligence analyst may not have the artillery piece
to fire the round on a test range, while the MASINT analyst has
multispectral recordings of it being used in the field.

As with many intelligence disciplines, it can be a challenge to
integrate the technologies into the active services, so they can be
used by warfighters.[4] Of
all difficulties, operational users expressed the greatest
frustration with the MASINT requirements process under the DIA
Central MASINT Office, the responsible organization in 1997.
Specifically, customers were frustrated by a lack of feedback on
the status of their requirements. The auditors urged the creation
of a multi-user database of MASINT requests, status, and—consistent
with security—findings.[5]

Understanding
"Measurement" and "Signature"

In the context of MASINT, measurement pertains to
finite metric parameters of targets. Signature covers the
distinctive features of phenomena, equipment, or objects as they
are sensed by the collection instrument(s). The signature is used
to recognize the phenomenon, equipment, or object once its
distinctive features are detected.[1]
Another way to think of it is that a signature is a known norm,
such as a normal blood sugar in medicine. MASINT measurement
searches for differences from known norms, and characterizes the
signatures of new phenomena. For example, the first time a new
rocket fuel exhaust is measured, it would be a deviation from a
norm. When the properties of that exhaust are measured, such as its
thermal energy, spectral analysis of its light (i.e., spectrometry), etc.,
those properties become a new signature in the MASINT database.

Another way to describe MASINT is as "a "non-literal"
discipline. It feeds on a target's unintended emissive byproducts,
or "trails" - the spectral, chemical or RF emissions an object
leaves behind. These trails form distinctive signatures, which can
be exploited as reliable discriminators to characterize specific
events or disclose hidden targets."[6]

While there are specialized MASINT sensors, much of the MASINT
discipline involves analysis of information from other sensors. For
example, a SIGINT sensor may provide information on the specific
characteristics and capabilities of a radar beam, which would be
part of ELINT. That same sensor, however, may
provide information about the "spillover" of the main beam (side lobes), or the
interference its transmitter produces. Those incidental
characteristics are part of MASINT.

Putting these concepts together is challenging; MASINT
specialists themselves struggle with providing simple explanations
of their field.[7]
One attempt calls it the “CSI” of the intelligence community,[7]
in imitation of the television series Crime Scene Investigation. This is useful
only to the extent that it emphasizes how MASINT depends on a great
many sciences to interpret data, where COMINT would deal with the
meaning in an intelligible human message. Interpreting that message
is not trivial, in that it would require idiomatic knowledge of the
language involved, any specialized terminology being discussed, and
inferences about emotional states and other subtle clues.

Another possible definition calls it "astronomy except for the
direction of view."[7]
The allusion here is to observational astronomy being a set of
techniques that do remote sensing looking away from the earth
(contrasted with how MASINT employs remote sensing looking toward
the earth). Astronomers make observations in multiple
electromagnetic spectra, ranging through radio waves, infrared,
visible, and ultraviolet light, into the X-ray spectrum and beyond.
They correlate these multispectral observations and create hybrid,
often “false-color”
images to give a visual representation of wavelength and energy,
but much of their detailed information is more likely a graph of
such things as intensity and wavelength versus viewing angle.

Another analogy uses medicine as a basis.[8]
If you have been weighed, that is a gravity measurement, which will
be compared against signatures such as underweight, normal, and
overweight for your height, age, and build. Gravity measurements
properly fall under geophysical MASINT. Similarly, biopsies measure
tissue samples against normal cell signatures, and are a form of
materials MASINT.

National and
Multinational

There has been work on developing standardized MASINT
terminology and architecture in NATO.[9]
Other work addresses the disappointments of Non-Cooperative Target
Recognition.[10]
For this function, infrared beacons (infrared MASINT)
proved disappointing, but millimeter-wave recognition shows more
promise. Still, cooperative, network-based position exchange may be
crucial in preventing fratricide. The bottom line is that
MASINT cannot identify who is inside a tank or aircraft of
interest.

Numerous countries produce their own antisubmarine warfare
sensors, such as hydrophones, active sonar, magnetic anomaly detectors,
and other hydrographic sensors that are frequently considered too
"ordinary" to be called MASINT.

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China

China is not reported to be pursuing the more specialized MASINT
technologies,[11]
although it does produce its antisubmarine sensors.

Germany

Following the first successful launch on December 19, 2006,
about a year after the intended launch date, further satellites
were launched at roughly six-month intervals, and the entire system
of this five-satellite SAR Lupesynthetic aperture radar
constellation achieved full operational readiness on 22 July
2008.[12]

Italy

Italy and France are cooperating on the deployment of the
dual-use Orfeo civilian and military satellite system.[13]

Orfeo is a dual-use (civilian and military) earth observation
satellite network developed jointly between France and Italy. Italy
is developing the Cosmo-Skymed X-band polarimetric synthetic aperture
radar, to fly on two of the satellites.

United
Kingdom

United
States

Within the US Intelligence Community the Directorate of MASINT
and Technical Collections office of the Defense Intelligence Agency
is the central agency for MASINT. This was formerly called the
Central MASINT Office. For education and research, there is the
Center for MASINT Studies and Research of the Air Force Institute of
Technology.

Clearly, the National Reconnaissance
Office and National Security Agency work
in collecting MASINT, especially with military components. Other
intelligence community organizations also have a collection role
and possibly an analytic role. In 1962, the Central Intelligence
Agency, Deputy Directorate for Research (now the Deputy
Directorate for Science and Technology), formally took on ELINT and
COMINT responsibilities.[15]
"The consolidation of the ELINT program was one of the major goals
of the reorganization. ... it is responsible for:

Research, development, testing, and production of ELINT and
COMINT collection equipment for all Agency operations.

ELINT support peculiar to the penetration problems associated
with the Agent's reconnaissance program under NRO.

Maintain a quick reaction capability for ELINT and COMINT
equipment."

"CIA's Office of Research and Development was formed to
stimulate research and innovation testing leading to the
exploitation of non-agent intelligence collection methods. ... All
non-agent technical collection systems will be considered by this
office and those appropriate for field deployment will be so
deployed. The Agency's missile detection system, Project [deleted]
based on backscatter
radar is an example. This office will also provide integrated
systems analysis of all possible collection methods against the
Soviet antiballistic missile program is an example."[15]
It is not clear where ELINT would end and MASINT would begin for
some of these projects, but the role of both is potentially
present. MASINT, in any event, was not formalized as a US-defined
intelligence discipline until 1986.

MASINT from
clandestinely placed sensors

CIA took on a more distinct MASINT responsibility in 1987.[16]
The National Security Archive commented, "In 1987, Deputy Director
for Science and Technology Evan Hineman established ... a new
Office for Special Projects. concerned not with satellites, but
with emplaced sensors – sensors that could be placed in a fixed
location to collect signals intelligence or measurement and
signature intelligence (MASINT) about a specific target. Such
sensors had been used to monitor Chinese missile tests, Soviet
laser activity, military movements, and foreign nuclear programs.
The office was established to bring together scientists from the
DS&T’s Office of SIGINT Operations, who designed such systems,
with operators from the Directorate of Operations, who were
responsible for transporting the devices to their clandestine
locations and installing them.

Multinational
counterproliferation

All nuclear testing, of any level, was forbidden under the Comprehensive Test
Ban Treaty (CTBT), but there is controversy over whether the Comprehensive
Nuclear-Test-Ban Treaty Organization (CTBTO) will be able to
detect sufficiently small events. It is possible to gain valuable
data from a nuclear test that has an extremely low yield, useless
as a weapon but sufficient to test weapons technology. CTBT does
not recognize the threshold principle and assumes all tests are
detectable.

The CTBTO runs an International Monitoring System (IMS) of
MASINT sensors for verification, which include seismic, acoustic,
and radionuclide techniques. See National technical
means of verification for a discussion of the controversies
surrounding the ability of the IMS to detect nuclear tests.

Military
applications

Even though today's MASINT is often on the edge of technologies,
many of them under high security classification, the techniques
have a long history. Captains of warships, in the age of sail, used
his eyes, and his ears, and sense of touch (a wetted finger raised
to the breeze) to measure the characteristics of wind and wave. He
used a mental library of signatures to decide what tactical course
to follow based on weather. Medieval fortification engineers would
put their ear to the ground to obtain acoustic measurements of
possible digging to undermine their walls.

Non-cooperative target
recognition

At the leading edge of today's military requirements, which may
be solved with MASINT, is non-cooperative target recognition
(NCTR), which could, even with the failure of identification friend or
foe (IFF) systems, prevent friendly fire incidents. One problem
of such identification is when coalition partners use the same
equipment. During Desert
Storm, coalition partner Syria used the same Russian T-72 tanks and French aircraft used
by the coalition enemy Iraq. (Ives)
mentions NCTR as a key MASINT tactical application.

Littoral
Warfare

During the Cold War,
the focus of naval operations was "blue water" operations far from land.
In today's geopolitical environment, "green water" coastal areas,
and "brown water" inland waterways, which jointly form the littoral, create new shallow water
challenges for modern ships.[17]

Unattended ground
sensors

Another strong need where MASINT may help is with unattended
ground sensors (UGS).[18]
During the Vietnam
War, UGS did not provide the functionality desired in the McNamara Line and
Operation Igloo White. They have
improved considerably, but are still an additional capability for
humans on the ground, not usually replacing people altogether.

In the U.S., much of the Igloo White technology came from Sandia National
Laboratories, who subsequently designed the Mini Intrusion
Detection System (MIDS) family, and the U.S. Marine Corps's
AN/GSQ-261 Tactical Remote Sensor System (TRSS). Another major U.S.
Army initiative was the Remotely Monitored Battlefield Sensor
System (REMBASS), which it upgraded to Improved REMBASS (IREMBASS),
and now is considering REMBASS II. The REMBASS generations, for
example, increasingly intertwine interconnections of infrared MASINT, Magnetic
MASINT, seismic MASINT, and acoustic
MASINT

The UK and Australia also are interested in UGS. Thales Defence
Communications, a division of French Thales and formerly Racal, builds the Covert Local Area Sensor System
for Intruder Classification (CLASSIC) for use in 35 countries,
including 12 NATO members. Australia adopted the CLASSIC 2000
version, which, in turn, becomes part of the Australian Ninox
system, which also includes Textron Systems’ Terrain Commander
surveillance system. CLASSIC has two kinds of sensors: Optical
Acoustic Satcom Integrated Sensor (OASIS) and Air Deliverable
Acoustic Sensor (ADAS), as well as television cameras, thermal
imagers, and low-light cameras.

ADAS sensors were in a U.S. program, Army Rapid Force Projection
Initiative advanced concept technology demonstration (ACTD), using
OASIS acoustic sensors and central processing, but not the
electro-optical component. ADAS sensors are emplaced in clusters of
three or four, for increased detection capability and for
triangulation. Textron says
that the ADAS acoustic sensors can track fixed-wing aircraft,
helicopters, and UAVs as well as traditional ground threats.

ACTD added Remote Miniature Weather Station (RMWS), from System
Innovations. These RMWS measure temperature, humidity, wind
direction and speed, visibility and barometric pressure, which can
then be sent over commercial or military satellite links.

Employing UGS is especially challenging in urban areas, where
there is a great deal more background energy and a need to separate
important measurements from them. Acoustic sensors will need to
distinguish vehicles and aircraft from footsteps (unless personnel
detection is a goal), and things such as construction blasting.
They will need to discriminate among simultaneous targets. Infrared
imaging, for the urban environment, will need smaller pixels. If either the targets or
the sensor is moving, micro-electromechanical accelerometers will
be needed.

Research programs:
Smart Dust and WolfPack

Still more of an UGS research program, under DARPA, is Smart Dust, which is a
program for developing massively parallel networks of hundreds or
thousand "motes," on the order of 1 mm3.

Another DARPA program is WolfPack, a ground-based electronic
warfare system to be ready by 2010. WolfPack is made up of a "pack"
of "wolves." Wolves are distributed electronic detection nodes with
location and classification capability, which may use radiofrequency MASINT techniques
along with ELINT methods. The wolves could be hand,
artillery, or airdrop delivered. WolfPack may fit into an Air Force
program for a new subdiscipline of counter-ESM, as well as
Distributed Suppression of Enemy Air Defenses (DSEAD), an
enhancement on SEAD. If the Wolves
are colocated with jammers or other ECM, and they are very close to
the target, they will not need much power to mask the signatures of
friendly ground forces, in frequencies used for communications or
local detection. DSEAD works in a similar way, but at radar
frequencies. It may be interesting to compare this counter-ELINT
discipline with ECCM.

Disciplines

MASINT is made up of six major disciplines, but the disciplines
overlap and intertwine. They interact with the more traditional
intelligence disciplines of HUMINT, IMINT, and SIGINT. To be more confusing, while MASINT
is highly technical and is called such, TECHINT is another
discipline, dealing with such things as the analysis of captured
equipment.

An example of the interaction is "imagery-defined MASINT (IDM)".
In IDM, a MASINT application would measure the image, pixel by pixel, and try to identify
the physical materials, or types of energy, that are responsible
for pixels or groups of pixels: signatures. When the
signatures are then correlated to precise geography, or details of
an object, the combined information becomes something greater than
the whole of its IMINT and MASINT parts.

As with many branches of MASINT, specific techniques may overlap
with the six major conceptual disciplines of MASINT defined by the
Center for MASINT Studies and Research, which divides MASINT into
Electro-optical, Nuclear, Geophysical, Radar, Materials, and
Radiofrequency disciplines.[19]

The two sets are not mutually exclusive, and it is entirely
possible that as this newly recognized discipline emerges, a new
and more widely accepted set will evolve. For example, the DIA list
considers vibration. In the Center for MASINT Studies and Research
list, mechanical vibrations, of different sorts, can be measured by
geophysical acoustic, electro-optical laser, or radar sensors.

Basic
interaction of energy sources with targets

Remote sensing depends on the interaction of a source of energy
with a target, and energy measured from the target.[21] In
the "Remote Sensing" diagram, Source 1a is an independent natural
source such as the Sun. Source 1b is a source, perhaps manmade,
that illuminates the target, such as a searchlight or ground radar
transmitter. Source 1c is a natural source, such as the heat of the
Earth, with which the Target interferes.

The Target itself may produce emitted
radiation, such as the glow of a red-hot object, which
Sensor 2 measures. Alternatively, Sensor 1 might measure, as
reflected radiation, the interaction of the Target
with Source 1a, as in conventional sunlit photography. If the
energy comes from Source 1b, Sensor 1 is doing the equivalent of
photography by flash.

Source 3a is under the observer's control, such as a radar
transmitter, and Sensor 3b can be tightly coupled to Source 3. An
example of coupling might be that Sensor 3 will only look for
backscatter radiation after the speed-of-light
delay from Source 3a to the target and back to the position of
Sensor 3b. Such waiting for a signal at a certain time, with radar,
would be an example of electronic
counter-countermeasures (ECCM), so that a signal jamming
aircraft closer to Sensor 3b would be ignored.

A bistatic remote sensing system would separate
source 3a from sensor 3b; a multistatic system could have multiple
pairs of coupled sources and sensors, or an uneven ratio of sources
and sensors as long as all are correlated. It is well known that
bistatic and multistatic radar are a potential means of defeating
low-radar-observability aircraft. It is also a requirement, from
operations personnel concerned with shallow water[22]
operations.

Techniques such as synthetic aperture have source 3a and sensor
3b colocated, but the source-sensor array takes multiple
measurements over time, giving the effect of physical separation of
source and sensor.

Any of the illuminations of the target (i.e., Source 1a, 1b, or
3a), and the returning radiation, can be affected by the
atmosphere, or other natural phenomena such as the ocean, between
source and target, or between target and sensor.

Observe that the atmosphere comes between the radiation source
and the target, and between the target and the sensor. Depending on
the type of radiation and sensor in use, the atmosphere can have
little interfering effect, or have a tremendous effect requiring
extensive engineering to overcome.

First, the atmosphere may absorb part of the energy passing
through it. This is bad enough for sensing if all wavelengths are
affected evenly, but it becomes much more complex when the
radiation is of multiple wavelengths, and the attenuation differs
among wavelengths.

Second, the atmosphere may cause an otherwise tightly collimated
energy beam to spread.

Classes of
sensor

Sensing systems have five major subcomponents:

Signal collectors, which concentrate the energy, as with a
telescope lens, or a radar antenna that focuses the energy at a
detector

Signal processing, which may remove artifacts from single
images, or compute a synthetic image from multiple views

Recording mechanism

Recording return mechanisms, such as digital telemetry from
satellites or aircraft, ejection systems for recorded media, or
physical return of a sensor carrier with the recordings
aboard.

MASINT sensors may be framing or scanning or synthetic. A
framing sensor, such as a conventional camera, records the received
radiation as a single object. Scanning systems use a detector that
moves across the field of radiation to create a raster or more
complex object. Synthetic systems combine multiple objects into a
single one.

Sensors may be passive or coupled to an active source (i.e.,
"active sensor"). Passive sensors receive radiation from the
target, either from the energy the target emits, or from other
sources not synchronized with the sensor.

Most MASINT sensors will create digital recordings or
transmissions, but specific cases might use film recording, analog
recording or transmissions, or even more specialized means of
capturing information.

Passive
sensing

The instantaneous field of view (IFOV) is the
area from which radiation currently impinges on the detector. The
swath width is the distance, centered on the
sensor path, from which signal will be captured in a single scan.
Swath width is a function of the angular field of
width (AFOV) of the scanning system.

Push broom sensors either
have a sufficiently large IFOV, or the scan moves fast enough with
respect to the forward speed of the sensor platform, that an entire
swath width is recorded without movement artifacts. These sensors
are also known as survey or wide
field devices, comparable to wide angle lenses on
conventional cameras.

Whisk broom or
spotlight sensors have the effect of stopping the
scan, and focusing the detector on one part of the swath, typically
capturing greater detail in that area. This is also called a
close look scanner, comparable to a telephoto lens
on a camera.

Passive sensors can capture information for which there is no
way to generate man-made radiation, such as gravity. Geodetic
passive sensors can provide detailed information on the geology or
hydrology of the earth.

Active
Sensors

Active sensors are conceptually of two types, imaging and
non-imaging. Especially when combining classes of sensor, such as
MASINT and IMINT, it can be hard to define if a given MASINT sensor
is imaging or not. In general, however, MASINT measurements are
mapped to pixels of a clearly imaging system, or to geospatial
coordinates known precisely to the MASINT sensor-carrying
platform.

In MASINT, the active signal source can be anywhere in the
electromagnetic spectrum, from radio waves to X-rays, limited only
by the propagation of the signal from the source. X-ray sources,
for example, must be in very close proximity to the target, while
lasers can illuminate a target from a high satellite orbit. While
this discussion has emphasized the electromagnetic spectrum, there
are also both active (e.g., sonar) and passive (e.g., hydrophone and microbarograph) acoustic sensors.

Quality of
Sensing

Several factors make up the quality of a given sensor's
information acquisition, but assessing quality can become quite
complex when the end product combines the data from multiple
sensors. Several factors, however, are commonly used to
characterize the basic quality of a single sensing system.

Spatial resolution defines the correspondence
between each recorded pixel and the square real-world area that the
pixel covers.

Spectral resolution is the number of discrete
frequency (or equivalent) bands recorded in an individual pixel.
Remember that relatively coarse spectral resolution from one
sensor, such as the spectroscopic analyzer that reveals a "bush" is
painted plaster, may greatly enhance the ultimate value of a
different sensor with finer spectral resolution.

Radiometric resolution is the number of levels
of energy recorded, per pixel, in each spectral band.

Temporal resolution describes the intervals at
which the target is sensed. This is meaningful only in synthetic
imaging, comparison over a longer time base, or in producing
full-motion imagery.

Geospatial resolution is the quality of
mapping pixels, especially in multiple passes, to known geographic
or other stable references.

Cueing

Cross-cueing is the passing of detection,
geolocation and targeting information to another sensor without
human intervention.[23] In a
system of sensors, each sensor must understand which other sensors
complement it. Typically, some sensors are sensitive (i.e., with a low incidence of false
negatives) while others have a low incidence of false
positives. A fast sensitive sensor that covers a large area, such
as SIGINT
or acoustic, can pass coordinates of a target of interest to a
sensitive narrowband RF spectrum analyzer for ELINT or a
hyperspectral electro-optical sensor. Putting sensitive and
selective, or otherwise complementary sensors, into the same
reconnaissance or surveillance system enhances the capabilities of
the entire system, as in the Rocket Launch Spotter.

When combining sensors, however, even a quite coarse sensor of
one type can cause a huge increase in the value of another, more
fine-grained sensor. For example, a highly precise visible-light
camera can create an accurate representation of a tree and its
foliage. A coarse spectral analyzer in the visible light spectrum,
however, can reveal that the green leaves are painted plastic, and
the "tree" is camouflaging something else. Once the fact of
camouflage is determined, a next step might be to use imaging radar
or some other sensing system that will not be confused by the
paint.

Cueing, however, is a step before automatic target
recognition, which requires both extensive signature
libraries and reliable matching to it.